Energy Efficiency

Question 1

How do you work out the efficiency of an appliance?

Answer 1

Useful energy out / total energy in X 100

Question 2

Out of the three energy types : Heat, sound and kinetic is not useful when a car is driven?

Answer 2

Heat

Sound

Question 3

If a kettle needs 500 joules to operate it and 50 joules are used for sound , how many Jules are left for heat?

Answer 3

450J

Question 4

A speaker uses 600J and uses 60J for sound , how efficient is it?

Answer 4

10%

Question 5

Complete the following statement

“energy can be transfered but can’t be…”

Answer 5

Destroyed